Community organization and resilience

This project explores processes that structure plant and soil microbial communities and how these process relate to exotic plant invasion. The most important recent product is Liao et al. (2015) in which we found that local plant species richness can affect soil biota in ways that can increase the competitive effects of natives against an aggressive exotic invader; thus, our results suggest a mechanism by which species diversity might provide resistance to exotic invasion. A second key discovery was the existence of a form of detection and avoidance mechanism among the roots of related Pseudoroegneria genotypes that was substantially stronger than that in unrelated genotypes. If decreased growth after contact results in reduced root overlap, and reduced root overlap corresponds with reduced productivity, then variation in detection and avoidance among related and unrelated ecotypes may contribute to how genotypic diversity in Pseudoroegneria increases local productivity. On a similar note, we have found that varietal diversity in plantings of winter wheat significantly increases the mean seed head size of individual plants, relative to when the same varietals are grown in monocultures. This has the potential to lead to interesting uses of diverse varietal mixtures to increase winter wheat productivity. This work is still in progress.